The treatment with nicotine-containing products today produces either too small quantities of nicotine in plasma and/or plasma profiles with a too flat and/or slow peak. The desired plasma profile is one that has a faster uptake of nicotine than other marketed treatment products. To solve this problem nicotine in its base form is preferred. Nicotine in its base form is readily absorbed through the oral mucosa but is highly volatile and subject to oxidative degradation. The available nicotine salts are more stable compounds but are not as readily absorbed as the free base. In order to deal with the volatility and stability problems of the free base different techniques are possible.
In U.S. Pat. No. 5,939,100 nicotine in its base form is incorporated in degradable starch microspheres. The use of degradable starch microspheres with incorporated nicotine gives a 3-dimensional matrix releasing the nicotine in a rather sustained fashion depending on both binding properties, nicotine-starch matrix and the biological degradation profile of the microspheres.
In WO 91/09599 an inclusion complex is produced between nicotine and β-cyclodextrin. The release of nicotine from the produced complex was filled in a porous bag of synthetic material (type tea bag) and the plasma profile was measured with a peak nicotine concentration (8 ng/ml) after approx. 45 min. in humans. The release is highly dependent on the affinity of nicotine to β-cyclodextrin and considered rather slow.
In U.S. Pat. No. 4,967,773 synthetic silica is used together with nicotine. The rational for this is to ensure the stability in a lozenge where nicotine together with silica could be mixed with lactose. The manipulation is done due to the formulation of a product where incompatible constituents (nicotine and lactose) are desired.
In U.S. Pat. No. 4,907,605 nicotine is absorbed in different water insoluble materials, e.g. paper, cellulose acetate, polyethylene or polypropylene. The sorbed nicotine is to be released slowly in an oral environment.
In U.S. Pat. No. 6,264,981 solid solutions of different active principals with a dissolution agent are presented. Nicotine is mentioned as an active principal together with a list of other substances.
None of the above-mentioned documents has addressed the need for a truly rapid release and absorption of nicotine through the oral mucosa in combination with high physical and chemical stability. The need for a solid carrier is evident but the combination of sorbing nicotine in a solid matrix is not just a stability concern but equally, if not more important, are the release properties from the carrier.